ORA-16069: Archive Log standby database activation identifier mismatch

I was Testing "Using a standby database for Read/Write for testing and Convert back to standby mode using Flasback"

Step followed :
Standby database :
1) alter database recover managed standby database finish ;
2) create restore point Before_DR_Test;
3) alter database commit to switchover to primary;
4) Startup force;
5) Create table , select data, etc
6) Complete any testing for read/write operation

Convert back to Standby :

7) startup mount force;
8) flashback database to restore point Before_DR_Test;
9) alter database convert to physical standby;
10) startup mount force;
11) alter database recover managed standby database disconnect;

All succeed and managed to convert the database in standby mode, but its failing to accept any new archive log generated at primary database. I am getting following error in standby database alert.log

RFS[10]: Activation ID mismatch: found 0x99d06db8 expected 0x99d0b54

ORA-16069: Archive Log standby database activation identifier mismatch